Are all points in the universe connected?

Question

Is it true that every point in the universe is connected or could be so theoretically? If so how is this mediated?

Is it through the quantum nature of the fabric of space or is it through the interrelationships of the gravity fields throughout the universe. From the gravity fields of single solar systems affecting each other to galaxies and galactic clusters as if they gravitational energy of each field has a knock-on effect on the next field?

Related: http://physics.stackexchange.com/q/1787/2451 – Qmechanic May 06 '13 at 18:07 — Qmechanic, May 06 '13 at 18:07
What kind of connection are you talking about? – David Z May 06 '13 at 18:45 — David Z, May 06 '13 at 18:45

score 5 · Accepted Answer · answered May 06 '13 at 18:07

All points in the observable universe are "connected" in the sense that they can be acted upon by forces that have an infinite range (gravity and electromagnetism).

However, points that are outside of our cosmological horizon (due to the expansion of the universe) are no longer causally connected with points in our local vicinity, since they are receding from us faster than light. The same is true of points that are inside the event horizon of a black hole.

score 2 · Answer 2 · answered May 06 '13 at 18:28

2

On space-time, the useful notion of points are events. Only events that are separated by time-like curves are causally connected. Causal connectedness implies that fields happening at one of the events can influence fields happening at the other. Events that are separated by space-like curves are not causally connected, they might be still connected indirectly through other events in their past or future.

The observable universe seems to be topologically trivial, that is, all causally connected paths that connect two given events are deformable into each other, i.e: no torii that can trap inequivalent classes of paths. if the topology of the universe is nontrivial behind event horizons of black holes, that topological information is inaccessible to us, and hence, not part of the observable universe.

answered May 06 '13 at 18:28

lurscher

14,423

What would be the observable symptoms of a nontrivial topology? – Deer Hunter May 07 '13 at 04:21
Thanks for the answers. I didnt think about it like that. However, is there any truthto my idea of the gravitational fields abound in space affecting each other because of their interaction – MICHAEL TAYLOR May 07 '13 at 15:19
2

@DeerHunter "Compactification" for example. The universe becomes a three dimensional analogue of, for example, a torus, sphere or cylinder: you can in theory keep going on a straight line (geodesic) in such a spacetime and eventually come back to your beginning point. An observable sign might be multiple views from the Earth of the same object at different times in its history. Some astronomers have claimed such observations from time to time: I don't know how seriously they are taken. – Selene Routley Aug 10 '15 at 02:14

Are all points in the universe connected?

2 Answers2